Muzzle loading bullet with gas seal

ABSTRACT

A projectile or bullet for a muzzle loading firearm that has a fixedly attached skirt as a gas seal. The projectile is a full-bore bullet that has high velocity and high accuracy and is easy to load. The bullet includes a rear body portion covered with skirt made of a different material than the body to form a gas seal when the projectile is fired. In a preferred embodiment, the skirt material is plastic, paper or nylon. The body portion of the projectile may be covered by a jacket. The nose portion of the bullet may incorporate a ballistic tip. In some embodiments, the rear of the bullet body is indented to allow the expanding gases at ignition to expand the rear of the bullet to further seal the combustion behind the bullet and to further seal the skirt to the bullet.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention generally relates to the field of projectiles for firearms, and more specifically relates to projectiles for muzzle loading firearms.

2. Background Art

Muzzle loading firearms have a long history. Modem muzzle loading firearms continue to find favor today with hobbyists and purists who use them for hunting and sport shooting. Although the principle of muzzle loading has remained relatively constant, various improvements have been made in an attempt to alleviate past problems and improve the speed, distance and accuracy of the bullet. For example, some modern muzzle loading bullets have copper jacketing or hydraulic tips. See U.S. Pat. No. 6,675,718 issued to Parker (the inventor of the present case), which is incorporated herein by reference.

To alleviate some of the previous problems with loading a bullet into a muzzle-loading firearm, a sabot was designed to replace the conventional wad. A sabot is typically a plastic sleeve that holds the bullet during loading and discharge, and then falls away after leaving the barrel of the gun. Sabots typically provide a gas seal that improves the muzzle velocity of the bullet. However, the sabot suffers from some disadvantages. For example, the sabot may split upon firing or ignition, causing increased inaccuracy in the flight characteristics of the bullet. In addition, a bullet is typically placed within a cylindrical portion of the sabot, between the bullet and the barrel. As a result, full-bore bullets cannot be loaded or shot using traditional sabots. Sabots are also more cumbersome during loading since they require two pieces to be handled.

Some of the modern muzzle loading bullets are no longer full-bore to eliminate the difficulty of loading the bullet. An example of a modern bullet is described in U.S. Pat. No. 5,458,064 issued to R. M. Kearns. This bullet has a gas check member that frictionally and resiliently engages the base of the bullet. The gas check member is manually attached prior to loading and detaches upon exiting the barrel after firing. Bullets of this type are popular, and work well where shooting of bullets that are not full-bore is allowed. However, many states within the United States require the use of muzzle loading bullets that have full-bore diameter for certain hunting seasons. Bullets such as those described in Kearns that are less than full-bore are not fully compliant with state law in some states that require hunting with full-bore bullets. Thus a more accurate and high velocity bullet is needed that is full-bore and yet still easy to load.

DISCLOSURE OF INVENTION

According to a preferred embodiment, a full-bore projectile or bullet includes a rear body portion having a reduced diameter that is covered with a skirt made of a different material than the body to form a gas seal when the projectile is fired. In a preferred embodiment, the skirt material is plastic, paper or nylon. The body portion of the projectile is preferably covered by a jacket. The nose portion of the bullet preferably incorporates a ballistic tip.

In some embodiments, the base or rear of the bullet body is indented to allow the expanding gases at ignition to expand the rear of the bullet to further seal the combustion behind the bullet and to further seal the skirt to the bullet. The shape of the indention may be concave, triangular, slotted, or another suitable shape.

An advantage of some embodiments of the present invention is increased terminal energy which gives higher knockdown energy and provides for a more sure kill when hunting.

Another advantage of the present invention is that it can be used in conjunction with jacketing and ballistic tips to obtain a wide range of performance characteristics to be optimized for the desired use and/or type of game to be hunted.

The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and:

FIG. 1 is a cross-sectional view of a projectile in accordance with a first embodiment;

FIG. 2 is a left end view of the projectile shown in FIG. 1;

FIG. 3 is a cross-sectional view of a projectile in accordance with a second embodiment;

FIG. 4 is a left end view of the projectile shown in FIG. 3;

FIG. 5 is a cross-sectional view of a projectile in accordance with a third embodiment;

FIG. 6 is a left end view of the projectile shown in FIG. 5;

FIG. 7 is a cross-sectional view of a projectile in accordance with a fourth embodiment;

FIG. 8 is a left end view of the projectile shown in FIG. 7;

FIG. 9 is a cross-sectional view of a projectile in accordance with a fifth embodiment;

FIG. 10 is a left end view of the projectile shown in FIG. 9;

FIG. 11 is a cross-sectional view of a projectile in accordance with a sixth embodiment;

FIG. 12 is a cross-sectional view of a projectile in accordance with a seventh embodiment;

FIG. 13 is a cross-sectional view of a projectile in accordance with an eighth embodiment; and

FIG. 14 is a cross-sectional view of a projectile in accordance with a ninth embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to FIG. 1, a bullet 100 is one suitable configuration for a projectile in accordance with a first embodiment. Bullet 100 is preferably configured for use in muzzle loading firearms. The bullet is generally cylindrically shaped with a tapered nose 102 as is common practice in the art. Bullet 100 includes a body 110 and a skirt 120. Body 110 includes a rear portion 112 of reduced diameter. The body 110 is made of a suitable material such as lead. In some embodiments, the body 110 is jacketed with a suitable metal such as copper that provides more rigidity to the bullet than lead alone. The skirt 120 is made of a different material than the body 110. The skirt material and dimensions are preferably chosen to: a) ensure a proper gas seal; b) enhance ease of loading; c) establish bore to bullet fit to insure the bullet does not move after being positioned on the powder; and d) establish sufficient engaging of the rifling as to ensure stabilization and accuracy. The skirt is preferably made from plastic, nylon, paper or a soft metal. The length and thickness of the skirt will be dictated by: a) the overall bullet length and rifle twist; b) the caliber of the bullet; c) state or other government legal bullet length requirements; and d) the desired application or use of the bullet. The skirt 120 is fixedly attached to the body 110 and provides a gas seal for the bullet when fired. The skirt when installed on the body and a portion of the body 110 has a diameter equal to or slightly greater than the bore diameter of the intended firearm.

FIG. 2 illustrates a left end view of the bullet 100 in FIG. 1. A rear surface 130 of the bullet 100 includes a reduced diameter portion 112 of the bullet body 110 surrounded by the skirt 120, as shown in FIGS. 1 and 2.

Referring now to FIG. 3, a bullet 100 is shown in accordance with a second embodiment. Bullet 100 includes a body 110 and a skirt 120. The bullet has a concave surface 140 on the left end of the bullet shown in FIG. 3. The rear edge of the skirt 150 is also preferably indented in a concave shape to form part of the concave surface 140 of the bullet 100. The concave surface 140 allows the expanding gases at ignition to expand or “upset” the concave surface 140 of the bullet to further seal the combustion behind the bullet and to further seal the skirt 120 to the bullet body 110. The remaining details of bullet 100 in FIG. 3 are similar to those corresponding features in accordance with the first embodiment described above.

FIG. 4 illustrates a left side view of the bullet 100 in FIG. 3. The rear edge 150 of the skirt 120 and the reduced diameter portion 112 form the concave surface 140.

Referring now to FIG. 5, a bullet 100 is shown in accordance with a third embodiment. Bullet 100 includes a body 110 and a skirt 120. The bullet 100 has an indented surface 142 on the rear portion 112 of the body 110. The indention 142 is a cone shaped opening in the reduced diameter portion 112. The indention 142 appears as two beveled faces forming a triangular shape cut out of the rear portion when viewed in the cross-sectional view of FIG. 5. The rear edges of the skirt 150 are preferably not indented. Similar to the previous embodiment, the indented rear portion allows the expanding gases at ignition to expand the rear of the bullet at ignition. The remaining details of bullet 100 in FIG. 5 are similar to those corresponding features in accordance with the first and second embodiments described above.

FIG. 6 illustrates a left side view of the bullet 100 described above with reference to FIG. 5. The rear edge 150 of the skirt 120 and the reduced diameter portion 112 with its conical indentation 142 are visible.

Referring now to FIG. 7, a bullet 100 is shown in accordance with a fourth embodiment. Bullet 100 includes a body 110 and a skirt 120. The bullet 100 has a indented surface 144 on the reduced diameter portion 112 of the body 110. The indention is a cylindrical opening in the rear portion of the body. The indention appears as a slot in the base when viewed in the cross-sectional view of FIG. 7. The rear edges 150 of the skirt 120 are preferably not indented. Similar to the previous embodiments, the indented rear portion 144 of the reduced diameter portion 112 of body 110 allows the expanding gases at ignition to expand the rear of the bullet at ignition.

The skirt in FIG. 7 further illustrates an additional feature in accordance with the preferred embodiments. The skirt 120 includes ring slots 164. The ring slots 164 are annular channels in the outer surface of the skirt. The ring slots 164 are an example of a skirt not being full-bore across the entire length of the skirt. The ring slots could be filled with a lubricant or another material 166 (such as grease or wax) to affect the sealing, lubricating or loading characteristics. The remaining details of bullet 100 in FIG. 7 are similar to those corresponding features in accordance with the other three embodiments described above.

FIG. 8 illustrates a side view of the bullet 100 described above with reference to FIG. 7. The rear edges 150 of the skirt 120 and the reduced diameter portion 112 with its indented surface 144 are visible.

Referring now to FIG. 9, a bullet 100 is shown in accordance with a fifth embodiment. Bullet 100 includes a body 110 that includes a reduced-diameter portion 112, and a skirt-cup 122. The skirt-cup 122 is fixed to the base of the bullet 100 and performs the same function of the skirt 120 in the previous embodiments. The skirt-cup preferably completely surrounds the reduced diameter portion 112 of the bullet body 110 such that no part of the reduced diameter portion 112 is exposed, as shown in FIGS. 9 and 10. This embodiment could more securely attach the skirt-cup 122 to the reduced diameter portion 112 and would give further assurance the bullet body 110 would not shoot out of the skirt-cup 122. The skirt-cup 122 may have an indented surface 160 on the rear portion of the skirt-cup, as shown in FIG. 9. Similar to the previous embodiments, the indented rear portion of the skirt-cup allows the expanding gases at ignition to expand the rear of the skirt-cup and bullet at ignition. The remaining details of bullet 100 in FIG. 7 are similar to those corresponding features in accordance with the other embodiments described above.

FIG. 10 illustrates a left end view of the bullet 100 in FIG. 7. The rear surface 160 of the skirt-cup 122 is visible. Note that the reduced diameter portion 112 of bullet body 110 is shown in phantom in FIG. 10 because the skirt-cup 122 completely covers the end of the reduced-diameter portion 112, as shown in FIG. 9.

Referring to FIG. 11, a bullet 100 in accordance with a fifth embodiment is shown further incorporating a hydraulic ballistic tip 170 in combination with the preferred embodiments shown in FIG. 1 above. One suitable configuration for the hydraulic ballistic tip 170 is shown and described in the inventor's previously-issued U.S. Pat. No. 6,675,7118. The hydraulic ballistic tip can be advantageously combined with each of the embodiments described above to obtain a wide range of performance characteristics to be optimized for the desired use and type of game to be hunted.

Referring to FIG. 12, a bullet 100 is shown having a stepped body. The step is a change in the diameter of the bullet body 110 in a middle portion of the body between the reduced diameter portion 112 and a reduced point portion 190. The step determines how much of the bullet 110 has a full-bore diameter. In FIG. 12, portion 180 of the bullet 100 represents the portion of the bullet body 110 that is full-bore. In a preferred embodiment, the full-bore portion 180 of the body 110 is less than about 25 percent of the overall length of the bullet that is full bore, which includes the length of the skirt 120 that is full bore. This allows the bullet to be easily loaded due to the relatively small portion 180 of the bullet body 110 that is full-bore. Thus, in a preferred embodiment, a portion of the bullet body is full-bore in addition to at least a portion of the skirt that is full-bore. The features of a stepped body and the hydraulic ballistic tip can be advantageously combined with each of the embodiments described above. Further, the bullet 100 in each embodiment described herein may be jacketed, preferably with copper. The jacketing may vary in thickness over the various parts of the bullet body to accomplish the intended bullet use and game to be taken. The bullet 100 in FIG. 12 is shown jacketed, as indicated by the thick line at the border of the bullet body 110 indicating the presence of the jacket. Jacketing of the bullet also reduces the user's exposure to lead. Known jacketed full-bore bullets are difficult to load. However, by using a jacketed body 110 with a skirt 120 or skirt-cup 122 that is permanently attached to the bullet body 110, the result is a full-jacketed bullet that is full-bore, but still easy to load.

Skirt 120 and skirt-cup 122 are permanently attached to the reduced-diameter portion 112 of the bullet body 110. This permanent attachment assures that the skirt flies with the bullet, rather than separating from the bullet upon exiting the barrel of a gun. This permanent attachment is in contrast to known sabots, which detach from the bullet and fall away once the sabot leaves the barrel, and is also in contrast to the bullet disclosed in the Kearns patent (discussed in the Background Art section above), which includes a gas check member that temporarily attaches to the bullet when loading, but also falls off the bullet once the bullet leaves the barrel.

Skirt 120 and skirt-cup 122 may be attached to the reduced-diameter portion 112 of the bullet using any suitable means of permanent attachment, including friction-fit, adhesives, fasteners, and other mechanical retention mechanisms that hold the skirt 120 and skirt cup 122 in place. One suitable example of mechanical retention mechanisms that help to hold a skirt 120 or skirt cup 122 in place is shown in FIG. 13. The reduced diameter portion 112 of body 110 includes one or more barbs 300 that engage the skirt 120 when the skirt 120 is slid onto the reduced-diameter portion 112. Such barbs 300 could be formed, for example, by forcing a sharp knife-edged tool into the side cylindrical wall of the reduced diameter portion 112 at an angle. In addition, one or more recesses could be formed in the reduced-diameter portion 112 with corresponding raised portions in the skirt 120 or skirt-cup 122 that allow the skirt 120 to snap permanently to place. The preferred embodiments expressly extend to any and all methods for attaching the skirt 120 and skirt cup 122 to a reduced-diameter portion 112 of a bullet body 110, including the use of one or more suitable mechanical retention mechanisms.

The preferred embodiments illustrated in FIGS. 1-13 all show a cylindrically-shaped reduced-diameter portion 112, and a corresponding cylindrically-shaped skirt 120 and skirt-cup 122. This configuration makes for ease of manufacturing, because the bullet body 110 may be cast, swaged, mechanically stamped or turned to provide the reduce-diameter portion 112 in this cylindrical shape, and plastic tubing could then be used to fabricate the skirt 120 or skirt-cup 122. Note, however, that the preferred embodiments expressly extend to non-cylindrical configurations as well. For example, the reduced-diameter portion 112 could have tapered side walls, as shown in FIG. 14, with the skirt 120 having a corresponding taper to fit on the tapered sidewalls. This tapered configuration is shown as one example of a non-cylindrical configuration. The preferred embodiments expressly extend to any and all configurations for permanently attaching a skirt or skirt-cup that is made of a first material to a bullet body that is made of a second, different material.

The combination of features shown herein results in a projectile that is relatively easy to manufacture and assemble and a reasonable cost. There are no pivot pins, set screws, or other things that are mechanically complex and prone to failure. A bullet in accordance with the preferred embodiments provides significantly greater damage when hunting with muzzle loaders, and provides a more humane kill by reducing the chance of an injured animal running off after being shot.

One skilled in the art will appreciate that many variations are possible within the scope of the present invention. For example, each of the rear portions of the bullet illustrated in FIGS. 1-7 could include a ballistic tip, as shown in FIGS. 11 and 12, and each could include the ring slots and other seal materials shown in FIG. 7. Thus, while the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that these and other changes in form and details may be made therein without departing from the spirit and scope of the invention. 

1. A projectile comprising: a body with at least a portion having a diameter at least as large as a bore size of an intended firearm; and a skirt made of a different material than the body and fixedly attached to a rear portion of the body.
 2. The projectile of claim 1 wherein the body comprises metal and the skirt comprises a non-metal material.
 3. The projectile of claim 1 wherein the skirt covers at least a portion of a rear portion of the body and at least a portion of the skirt has a diameter at least as large as a bore size of the intended firearm.
 4. The projectile of claim 1 wherein the skirt is a cylindrical sleeve surrounding a reduced diameter portion of a cylindrical rear portion of the body.
 5. The projectile of claim 1 wherein the body further comprises a rear portion having an indented surface.
 6. The projectile of claim 5 wherein the indented surface is concave.
 7. The projectile of claim 5 wherein the indented surface is conical.
 8. The projectile of claim 1 wherein a nose portion of the body includes a ballistic tip.
 9. The projectile of claim 1 wherein the diameter of the body steps down from a fill-bore diameter to a smaller diameter near a nose portion of the body.
 10. A projectile comprising: a body with at least a portion having a diameter at least as large as a bore size of an intended firearm and a stepped down portion having a reduced-diameter portion that is substantially smaller than the bore size; and a skirt-cup made of a different material than the body and fixedly attached to a rear portion of the body, the skirt-cup substantially covering the reduced-diameter portion.
 11. The projectile of claim 10 wherein the body comprises metal and the skirt-cup comprises a non-metal material.
 12. The projectile of claim 10 wherein the rear portion comprises an indented surface.
 13. The projectile of claim 12 wherein the indented surface is concave.
 14. The projectile of claim 12 wherein the indented surface is conical.
 15. The projectile of claim 10 wherein a nose portion of the body comprises a ballistic tip.
 16. The projectile of claim 10 wherein the diameter of the body steps down from a full-bore diameter to a smaller diameter near a nose portion of the body.
 17. A projectile comprising: a body with a rear portion, a middle portion and a point portion, wherein at least part of the middle portion of the body has a diameter at least as large as a bore size of an intended firearm and the rear portion has a diameter less than the bore size; and a skirt made of a different material than the body and fixedly attached to the rear portion of the body, wherein the skirt covers at least some of a rear portion of the body and at least a portion of the skirt has a diameter at least as large as a bore size of the intended firearm.
 18. The projectile of claim 17 wherein the body further comprises a stepped diameter at a point between the middle portion and the point portion.
 19. The projectile of claim 17 wherein the part of the middle body portion that has a diameter at least as large as a bore size is less than 25 percent of the portion of the skirt that has a diameter at least as large as the bore size.
 20. The projectile of claim 17 wherein the part of the middle body portion that has a diameter at least as large as a bore size is less than 25 percent of the portion of the skirt that has a diameter at least as large as the bore size.
 21. The projectile of claim 17 wherein the body further comprises a rear portion having an indented surface.
 22. The projectile of claim 21 wherein the indented surface is concave.
 23. The projectile of claim 17 wherein the skirt further comprises a plurality of annular channels in an outer surface of the skirt.
 24. The projectile of claim 17 wherein a nose portion of the body comprises a ballistic tip.
 25. The projectile of claim 24 wherein the ballistic tip is hydraulic.
 26. The projectile of claim 17 wherein the body of the bullet comprises a metal jacket made of a material harder than the material of the body.
 27. A projectile comprising: a body with a cylindrical rear portion, a middle portion, and a point portion, wherein at least part of the middle portion of the body has a diameter at least as large as a bore size of an intended firearm, and the length of the middle portion of at least bore size diameter is less than about 25 percent of the overall length of the projectile that is at least full bore; a cylindrical sleeve skirt surrounding a reduced diameter portion of the cylindrical rear portion of the body made of different material than the body and fixedly attached to the rear portion of the body, wherein the skirt covers at least some of a rear portion of the body and wherein at least a portion of the skirt has a diameter at least as large as a bore size of the intended firearm; a metal jacket made of a material harder than the material of the body covering a substantial portion of the body; and a ballistic tip in the nose portion of the body.
 28. A method for manufacturing a bullet comprising the steps of: forming a bullet body with at least a portion having a diameter at least as large as a bore size of an intended firearm; and fixedly attaching a skirt made of a different material than the body to a rear portion of the body.
 29. The method of claim 28 wherein the body comprises metal and the skirt comprises a non-metal material.
 30. The method of claim 28 wherein the skirt covers at least a portion of a rear portion of the body and at least a portion of the skirt has a diameter at least as large as a bore size of the intended firearm.
 31. The method of claim 28 wherein the skirt is a cylindrical sleeve surrounding a reduced diameter portion of a cylindrical rear portion of the body.
 32. The method of claim 28 wherein the body further comprises a rear portion having an indented surface.
 33. The method of claim 32 wherein the indented surface is concave.
 34. The method of claim 32 wherein the indented surface is conical.
 35. The method of claim 28 wherein a nose portion of the bullet body includes a hydraulic ballistic tip.
 36. The method of claim 28 wherein the diameter of the body steps down from a full-bore diameter to a smaller diameter near a nose portion of the body. 